This invention is directed to electronic power amplifiers and is particularly adapted to the field of musical instruments, e.g. electric guitar amplifiers. The electronic power amplifier is a device designed to amplify small signal voltages up to a point where these voltages can be reconverted into usable amounts of power and thus can be used to perform work. In the case of sound or audio applications the electrical power output of the amplifier is used to move the cone of the speaker to produce sound. In the case of radio frequency amplifiers the power output is spread to an antenna and radiates its power signal over long distances.
It is known in the art that the level of distortion as a function of maximum power outlet is more desirable than undistorted power output because when an amplifier is driven into output distortion, (past what is commonly called the "clipping point") desirable musical effects are produced. Among these effects is that the original sound of an electric guitar is totally changed due to the added harmonics caused by the output power distortion of the guitar amplifier, but up to the present time there has been, as far as applicant is aware, no means for controlling the clipping point of the amplifier. By providing a control as described hereinafter, the intensity of the distorted output power can be varied to accommodate the ever changing volume requirement of different acoustical environments, e.g. with relation to small rooms, large halls, etc.